JP5124905B2 - Method for producing metadiisopropylbenzene - Google Patents

Description

  The present invention relates to a method for producing metadiisopropylbenzene, and more specifically, a method for continuously producing metadiisopropylbenzene by an alkylation reaction and a transalkylation reaction using benzene and propylene as raw materials using a liquid aluminum chloride complex catalyst. The reaction to the target metadiisopropylbenzene is sufficiently advanced, and by-product of ethylisopropylbenzene and trimethylindane, which are impurities of metadiisopropylbenzene, and trimethylindane and isopropyltrimethylindane, which are substances causing a decrease in catalytic activity. The present invention relates to a manufacturing method for controlling the amount to a low level.

  A method of producing metadiisopropylbenzene by an alkylation reaction and a transalkylation reaction using benzene and propylene as raw materials using a liquid aluminum chloride complex catalyst is known (for example, see Patent Document 1).

  In the conventional production method, the liquid aluminum chloride complex catalyst to be used was usually added to the alkylation reaction step, but the catalytic activity decreased in the alkylation reaction, and the transalkylation reaction step in the subsequent step. However, since the catalytic activity has already been reduced, the transalkylation reaction rate is reduced, and the amount of metadiisopropylbenzene produced at the outlet of the transalkylation reaction step is reduced.

In general, as a way to solve this problem,
(1) Increasing the amount of catalyst added to the alkylation reaction step (2) Adding a new catalyst to the transalkylation reaction step (3) Transalkylation reaction using a method such as raising the temperature of the transalkylation reaction It is possible to increase the speed. However, when the methods (1) and (2) are used, the amount of the catalyst used increases, resulting in problems such as an increase in impurities due to side reactions and a cost problem due to an increase in the amount of aluminum chloride used. . On the other hand, when the reaction temperature is raised, a new problem arises that impurities due to side reactions increase and the reaction yield as a whole decreases.

  Here, the impurities due to the side reaction are, for example, ethyl isopropyl benzene, trimethyl indane and isopropyl trimethyl indane.

  Ethyl isopropyl benzene has a boiling point close to that of metadiisopropyl benzene, and it is difficult to separate them from each other by distillation. For this reason, if the amount of by-produced ethyl isopropyl besen in the reaction step increases, the purity of the target product meta-isopropyl benzene decreases.

  Trimethylindane is one of the causative substances for reducing the activity of liquid aluminum chloride complex catalysts. If there is a large amount of trimethylindane by-produced in the alkylation reaction process and transalkylation process, the catalytic activity decreases and the reaction rate decreases. The amount of metadiisopropylbenzene produced in the transalkylation reaction step is reduced. Trimethylindane has a boiling point close to that of metadiisopropylbenzene, and it is difficult to separate them from each other by distillation. For this reason, when the by-product amount of trimethylindane in the reaction process is increased, the purity of the target product meta-isopropylbenzene is lowered.

  Isopropyltrimethylindane is one of the causative agents that decrease the activity of liquid aluminum chloride complex catalysts. If the amount of by-produced isopropyltrimethylindane is large in the alkylation reaction process and transalkylation process, the catalyst activity decreases and the reaction rate decreases. For this reason, the amount of metadiisopropylbenzene produced in the transalkylation reaction step decreases.

  As described above, in the production of metadiisopropylbenzene, it is important to control the amount of impurities such as ethylisopropylbenzene, trimethylindane and isopropyltrimethylindane to a low level and to sufficiently promote the reaction to metadiisopropylbenzene. There was a need for further improvements.

JP-A-8-325175 (pages 1 to 4)

  In view of such circumstances, the present invention provides a method for continuously producing metadiisopropylbenzene by an alkylation reaction and a transalkylation reaction using benzene and propylene as raw materials using a liquid aluminum chloride complex catalyst. It is an object of the present invention to provide a method for producing metadiisopropylbenzene, which can sufficiently reduce the amount of by-produced substances that cause the decrease and allow the reaction to metadiisopropylbenzene to proceed sufficiently.

That is, the invention according to claim 1 is a method of reacting benzene and propylene using a liquid aluminum chloride complex catalyst, and includes at least an alkylation reaction step, a transalkylation reaction step, a catalyst removal step, and a rectification step. In the method for continuously producing metadiisopropylbenzene, the present invention relates to a method for producing metadiisopropylbenzene, which comprises the following steps A to C.
Process A: Recycling unreacted benzene and cumene fractions in the rectification process to the alkylation reaction process Process B: Recycling paradiisopropylbenzene and triisopropylbenzene fractions in the rectification process to the transalkylation reaction process Step C: Step of adding a liquid aluminum chloride complex catalyst divided into an alkylation reaction step and a transalkylation reaction step

The invention according to claim 2 is directed to the alkylation reaction step using the following formulas (1) and (2) for any aluminum chloride concentration in the alkylation reaction step and the transalkylation reaction step in the step C. The method for producing metadiisopropylbenzene according to claim 1, wherein the liquid aluminum chloride complex catalyst addition amount (C1) and the liquid aluminum chloride complex catalyst addition amount (C2) to the transalkylation reaction step are calculated and added. It is related to.
X1 = A × C1 / (P + B + CUM) (1)
X2 = A × (C1 + C2) / (P + B + CUM + PDC) (2)
(However, A: Aluminum chloride concentration in the complex catalyst [wt%], X1: concentration of aluminum chloride in the alkylation reaction step [wt%], X2: concentration of aluminum chloride in a transalkylation reaction step [wt%], C1: Liquid aluminum chloride complex catalyst addition amount [kg / H] to the alkylation reaction step, C2: Liquid aluminum chloride complex catalyst addition amount [kg / H] to the transalkylation reaction step, P: Fresh propylene supply amount [kg / H], B: supply amount of fresh benzene [kg / H], CUM: supply amount of unreacted benzene and cumene fraction [kg / H], PDC: supply amount of paradiisopropylbenzene and triisopropylbenzene fraction [ kg / H])

  The invention according to claim 3 is characterized in that in the step C, the concentration of aluminum chloride in the alkylation reaction step is equal to the concentration of aluminum chloride in the transalkylation reaction step by the formulas (1) and (2). 3. The method for producing metadiisopropylbenzene according to claim 1 or 2, wherein the amount of liquid aluminum chloride complex catalyst added to the acetylation reaction step and the transalkylation reaction step is calculated and added to each step. It is.

  In the invention according to claim 4, the addition amount of the liquid aluminum chloride complex catalyst to the alkylation reaction step and the transalkylation reaction step with respect to any aluminum chloride concentration in the alkylation reaction step and the transalkylation reaction step, The aluminum chloride concentration in each of the alkylation reaction step and the transalkylation reaction step is controlled by causing a computer to perform the calculation using (1) and (2), respectively. The present invention relates to a method for producing metadiisopropylbenzene.

  The invention according to claim 5 is characterized in that the transalkylation reaction step performs a transalkylation reaction using two or more reactors arranged in series. It concerns on the manufacturing method of described meta diisopropyl benzene.

  According to the present invention, in a method for continuously producing metadiisopropylbenzene by an alkylation reaction and a transalkylation reaction using benzene and propylene as raw materials using a liquid aluminum chloride complex catalyst, the entire liquid chloride added to the reaction step is added. Without changing the amount of the aluminum complex catalyst, by adding the liquid aluminum chloride complex catalyst divided into the alkylation reaction step and the transalkylation reaction step, and arbitrarily controlling the concentration of aluminum chloride in each step, It has become possible to provide a production method of metadiisopropylbenzene having an excellent effect that can reduce the generation of impurities and catalyst activity lowering cause substances due to side reactions, and can sufficiently proceed the reaction to metadiisopropylbenzene.

  A detailed description will be given based on FIG. 1 showing a flow chart showing an example of an aspect of the present invention. As shown in FIG. 1, in the present invention, a method for producing metadiisopropylbenzene in which benzene and propylene are reacted using a liquid aluminum chloride complex catalyst includes at least an alkylation reaction step 100, a transalkylation reaction step 200, and catalyst removal. It has process 300 and rectification process 400.

  The liquid aluminum chloride complex catalyst (hereinafter referred to as “complex catalyst”) used as the catalyst 1 is a complex catalyst in the form of a uniform solution composed of aluminum chloride, hydrogen chloride, and aromatic hydrocarbons. Here, as the aromatic hydrocarbon, one or a mixture of two or more of benzene, cumene, paradiisopropylbenzene, triisopropylbenzene and metadiisopropylbenzene is usually used. What is necessary is just to make it a uniform solution by stirring and mixing 0.5-1.0 mol hydrogen chloride and 2-10 mol aromatic hydrocarbon per 1 mol of aluminum chloride. In this case, the preparation temperature is preferably 20 to 70 ° C. If the preparation temperature is too high, the catalytic activity is lowered, and if it is too low, it takes a long time to obtain a homogeneous solution. The preparation time is not particularly limited, but is generally about 10 minutes to 10 hours.

  In the present invention, in the presence of a complex catalyst, the raw materials benzene 2 and propylene 3 are brought into contact with each other to perform an alkylation reaction, and then a transalkylation reaction is performed. At this time, the complex catalyst is added in the C step 4 divided into an alkylation reaction step and a transalkylation reaction step. Further, benzene, cumene, paradiisopropylbenzene, triisopropylbenzene, etc. separated and recovered from metadiisopropylbenzene in the rectification step described later may be recycled and supplied to the alkylation reaction step 100 or the transalkylation reaction step 200. However, as A step 5, a fraction having a lower boiling point than metadiisopropylbenzene such as benzene and cumene (hereinafter referred to as “recycled cumene”) is used in alkylation reaction step 100, and as B step 6, paradiisopropylbenzene and triisopropyl. A fraction having a boiling point higher than that of metadiisopropylbenzene such as benzene (hereinafter referred to as “recycled PDC”) is preferably recycled and supplied to the transalkylation reaction step 200.

In the present invention, the complex addition amount to the alkylation reaction step is determined by using the following formulas (1) and (2) for the addition amount of the complex catalyst to the alkylation reaction step and the transalkylation reaction step for any aluminum chloride concentration. A catalyst addition amount (C1) and a complex catalyst addition amount (C2) to the transalkylation reaction step are calculated, and the complex catalyst is dividedly added to the alkylation reaction step and the transalkylation reaction step. In addition, the following arithmetic expressions show a case where recycled cumene is supplied to the alkylation reaction step and recycled PDC is supplied to the transalkylation reaction step.
X1 = A × C1 / (P + B + CUM) (1)
X2 = A × (C1 + C2) / (P + B + CUM + PDC) (2)
(However, A: Aluminum chloride concentration in the complex catalyst [wt%], X1: concentration of aluminum chloride in the alkylation reaction step [wt%], X2: concentration of aluminum chloride in a transalkylation reaction step [wt%], C1: Complex catalyst addition amount [kg / H] to alkylation reaction step, C2: complex catalyst addition amount [kg / H] to transalkylation reaction step, P: fresh propylene supply amount [kg / H], B: Fresh benzene supply [kg / H], CUM: recycled cumene supply [kg / H], PDC: recycled PDC supply [kg / H])

  In the present invention, the aluminum chloride concentration in the alkylation reaction step and the aluminum chloride concentration in the transalkylation reaction step are calculated by calculating the complex catalyst addition amount required for each step according to the above formulas (1) and (2). C can be controlled to an arbitrary concentration by adding it in steps 4 separately. Since the reaction composition changes depending on the reaction conditions for alkylation and transalkylation, the amounts of recycled cumene and recycled PDC that are usually recycled from the rectification step described later are not always constant. Under such reaction conditions, by controlling the addition amount of the complex catalyst as described above, it has become possible to find optimum conditions for reducing the products due to side reactions. As described above, in order to control the aluminum chloride concentration in the alkylation reaction step and the transalkylation reaction step to an arbitrary concentration, it is necessary to constantly adjust the divided addition amount of the complex catalyst, which is complicated. When used and calculated by a computer or the like, the amount of catalyst added to the alkylation reaction step and the transalkylation reaction step can be calculated, and the adjustment of the amount of addition of the complex catalyst is easy.

  As described above, the complex catalyst is added separately to the alkylation reaction step and the transalkylation reaction step, so that a decrease in the catalyst activity in the alkylation reaction can be suppressed, and a highly active complex catalyst can be directly added to the transalkylation reaction step. Can be added. As a result, the production of trimethylindane and isopropyltrimethylindane, which are catalytic activity lowering substances, can be controlled to a low level, and a sufficiently high equilibrium achievement rate can be realized. In addition, since the boiling point of metadiisopropylbenzene, which is the target product, is close and the production of ethylisopropylbenzene and trimethylindane, which are difficult to separate from metadiisopropylbenzene in the rectification process described later, can be controlled at a low level, High metadiisopropylbenzene can be obtained.

  As one of the conditions, the catalytic activity is reduced by adding the complex catalyst separately in the alkylation reaction step and the transalkylation step so that the aluminum chloride concentration in the alkylation reaction step and the aluminum chloride concentration in the transalkylation reaction step are equal. It was found that the production of isopropyltrimethylindane, a causative substance, can be controlled to a low level, and a sufficiently high equilibrium achievement rate can be realized. In addition, it is possible to control the production of ethyl isopropyl benzene, which has a boiling point close to that of the target meta diisopropyl benzene and is difficult to separate from meta diisopropyl benzene in the rectification process described later, so that high purity meta diisopropyl Benzene can be obtained.

  The alkylation reaction of this invention should just contact benzene and propylene which are raw materials in presence of a complex catalyst. Specifically, propylene may be blown into a benzene solution containing a complex catalyst in the reactor. In addition to fresh benzene and propylene newly supplied from outside the reaction system, recycled cumene is supplied as a raw material for the alkylation reaction. The molar ratio of fresh benzene and propylene (benzene / propylene) newly supplied from outside the system is usually about ½.

  The amount of the complex catalyst used in the alkylation reaction is usually 0.05 to 1.0% by weight, preferably 0.1 to 0.5% by weight, more preferably 0.15 in terms of aluminum chloride concentration in the reaction solution. ~ 0.4 wt%. If the catalyst concentration is low, the reaction is slow, while if the concentration is too high, side reactions increase, and the amount of aluminum chloride used increases, which is uneconomical. In order to accelerate the alkylation reaction, 0.01 to 0.2 mol of hydrogen chloride may be added as a promoter to 1 mol of aluminum chloride. Reaction temperature is 50-150 degreeC normally, 50-120 degreeC is preferable and 60-100 degreeC is still more preferable. Cooling energy for reaction heat removal is excessively required at low temperatures, and side reaction products such as ethylisopropylbenzene, trimethylindane and isopropyltrimethylindane increase at high temperatures. The reaction pressure is generally from atmospheric pressure to 10-50 kPaG. The reaction time is generally 1 to 100 minutes although it depends on the reaction conditions.

  In the reaction solution obtained by the alkylation reaction, cumene, orthodiisopropylbenzene, paradiisopropylbenzene, triisopropylbenzene, and the like are present in addition to the target metadiisopropylbenzene and the raw material benzene. By the way, it is known that when the transalkylation reaction is sufficiently performed, these compounds reach a certain equilibrium concentration. The concentration of each compound in the equilibrium state is determined mainly by the ratio of the number of moles of isopropyl groups to the number of moles of phenyl groups (hereinafter referred to as “P / B”) and the temperature of the reaction raw material. In the case of B = 1.55, the equilibrium concentration of metadiisopropylbenzene is about 35% by weight. However, the reaction solution after the alkylation reaction is generally not in an equilibrium state. Compared to the equilibrium state, the concentration of the target metadiisopropylbenzene is low, and benzene, paradiisopropylbenzene, and triisopropylbenzene. The concentration of the species is high. Therefore, it is necessary to increase the concentration of metadiisopropylbenzene, which is the target product, by increasing the equilibrium achievement rate to bring the composition of the reaction solution closer to the equilibrium state. In order to achieve this object, the transalkylation reaction which is the next step is performed.

  As the raw material for the transalkylation reaction, an alkylation reaction liquid containing the above complex catalyst is used, and recycled PDC is further supplied. The amount of the complex catalyst used in the transalkylation reaction is usually 0.05 to 1.0% by weight, preferably 0.1 to 0.5% by weight, more preferably 0.8% by aluminum chloride concentration in the reaction solution. 15 to 0.4% by weight. If the catalyst concentration is low, the reaction is slow, while if the concentration is too high, side reactions increase, and the amount of aluminum chloride used increases, which is uneconomical. The transalkylation reaction may be performed using two or more reactors. In this case, the complex catalyst may be added to any reaction tank, but is preferably added to the first reactor. Reaction temperature is 50-150 degreeC normally, 50-120 degreeC is preferable and 60-100 degreeC is more preferable. The reaction is slow at low temperatures, and side reaction products such as ethyl isopropylbenzene, trimethylindane and isopropyltrimethylindane increase at high temperatures. The reaction pressure is generally from atmospheric pressure to 10-50 kPaG. The reaction time of the transalkylation reaction is generally 50 to 300 minutes, although it depends on the reaction conditions. The reaction solution of the transalkylation reaction thus obtained has a sufficiently high equilibrium achievement rate, that is, the concentration of the target metadiisopropylbenzene is sufficiently high and undesired impurities such as ethylisopropylbenzene and impurities. Thus, the concentrations of trimethylindane, which is a catalyst activity lowering substance, and isopropyltrimethylindane, which is a catalyst activity lowering substance, are kept low.

  In order to obtain metadiisopropylbenzene which is the target product from the obtained reaction solution of the transalkylation reaction, a usual method is used. For example, in the catalyst removal step, the complex catalyst is separated from the reaction mixture by a liquid separation operation, or the reaction mixture is washed with water or caustic to remove the complex catalyst. Thereafter, the oil layer obtained in the rectification step is distilled, and the target metadiisopropylbenzene fraction can be separated from a plurality of fractions composed of benzene, cumene, paradiisopropylbenzene, triisopropylbenzenes, and the like. At this time, each fraction other than the target product can be recycled to an alkylation reaction or a transalkylation reaction. By such a method, metadiisopropylbenzene which is the target product can be obtained.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereby.
Example 1
The reaction was carried out using the manufacturing process shown in the flowchart (FIG. 1) showing an example of the embodiment of the present invention. In addition to complex catalyst 1, benzene 2 and propylene 3, recycled cumene is continuously fed to A alkylation reaction process 100 by A process 5, and reaction liquid and complex catalyst from alkylation reaction process are fed to transalkylation process 200. The recycled PDC was continuously fed by the B process. The complex catalyst was added in portions so that the aluminum chloride concentration in each reaction tank of the alkylation reaction step 100 and the transalkylation step 200 was 0.22 wt%. P / B ratio in transalkylation process (propylene added isopropyl group / benzene added phenyl group molar ratio) 1.70, alkylation reaction process reaction tank temperature 79 ° C., transalkylation process reaction tank temperature 82 A continuous reaction was performed at ° C. As a result, the concentration of metadiisopropylbenzene (MDC) in the reaction solution in the steady state was 34.3% by weight, and the concentration of isopropyltrimethylindane (IPTMI) was 0.22% by weight. (EPB) was 790 ppm by weight with respect to MDC, and trimethylindane (TMI) was 0.11% by weight with respect to MDC.

Comparative Example 1
The same procedure as in Example 1 was conducted except that the complex catalyst and the recycled PDC were fed continuously to the reaction tank of the alkylation reaction step. As a result, the MDC concentration in the reaction solution in the steady state was 33.6% by weight, the IPTMI concentration was 0.27% by weight, EPB was 860 ppm by weight with respect to MDC, and TMI was 0.15% by weight with respect to MDC. In addition, since the IPTMI concentration, which is a causative agent for reducing the catalytic activity, increased from the Examples, the MDC concentration decreased and the impurity concentration relative to MDC also increased.
The results are shown in Table 1.

It is a flowchart which shows an example of embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Catalyst, 2 ... Raw material benzene, 3 ... Raw material propylene, 4 ... C process , 5 ... A process, 6 ... B process, 7 ... Metadiisopropylbenzene (MDC), 100 ... Alkylation reaction process, 200 ... Transalkylation Process, 300 ... Catalyst removal process, 400 ... Rectification process

Claims (5)

A method of reacting benzene and propylene using a liquid aluminum chloride complex catalyst, and continuously producing metadiisopropylbenzene having at least an alkylation reaction step, a transalkylation reaction step, a catalyst removal step, and a rectification step. In the method, the method includes the following steps A to C, the transalkylation reaction step is performed after the alkylation reaction step, and the catalyst removal step is water-washing or caustic washing of the reaction mixture of benzene and propylene, A process for producing metadiisopropylbenzene, which is a step of removing a complex catalyst without reusing it.
Process A: Recycling unreacted benzene and cumene fractions in the rectification process to the alkylation reaction process Process B: Recycling paradiisopropylbenzene and triisopropylbenzene fractions in the rectification process to the transalkylation reaction process Step C: Step of adding a liquid aluminum chloride complex catalyst divided into an alkylation reaction step and a transalkylation reaction step In step C, the amount of liquid aluminum chloride complex catalyst added to the alkylation reaction step using the following formulas (1) and (2) with respect to any aluminum chloride concentration in the alkylation reaction step and transalkylation reaction step ( The method for producing metadiisopropylbenzene according to claim 1, wherein the addition amount (C2) of the liquid aluminum chloride complex catalyst to C1) and the transalkylation reaction step is calculated and added.
X1 = A × C1 / (P + B + CUM) (1)
X2 = A × (C1 + C2) / (P + B + CUM + PDC) (2)
(However, A: Aluminum chloride concentration in the complex catalyst [wt%], X1: concentration of aluminum chloride in the alkylation reaction step [wt%], X2: concentration of aluminum chloride in a transalkylation reaction step [wt%], C1: Liquid aluminum chloride complex catalyst addition amount [kg / H] to the alkylation reaction step, C2: Liquid aluminum chloride complex catalyst addition amount [kg / H] to the transalkylation reaction step, P: Fresh propylene supply amount [kg / H], B: supply amount of fresh benzene [kg / H], CUM: supply amount of unreacted benzene and cumene fraction [kg / H], PDC: supply amount of paradiisopropylbenzene and triisopropylbenzene fraction [ kg / H]) In the step C, the alkylation reaction step and the formula (1) and (2) according to claim 2 so that the concentration of aluminum chloride in the alkylation reaction step is equal to the concentration of aluminum chloride in the transalkylation reaction step. The method for producing metadiisopropylbenzene according to claim 1 or 2, wherein the amount of liquid aluminum chloride complex catalyst added to the transalkylation reaction step is calculated and added to each step. The amount of liquid aluminum chloride complex catalyst added to the alkylation reaction step and the transalkylation reaction step with respect to an arbitrary aluminum chloride concentration in the alkylation reaction step and the transalkylation reaction step, the formula (1) according to claim 2, (4) controlling the aluminum chloride concentration in each of the alkylation reaction step and the transalkylation reaction step by causing a computer to calculate each of the metadiisopropylbenzenes according to any one of claims 1 to 3 Production method. The method for producing metadiisopropylbenzene according to any one of claims 1 to 4, wherein the transalkylation reaction step performs a transalkylation reaction using two or more reactors arranged in series. .

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